In fastening a rail to a concrete tie or the like according to a conventional method, the rail is placed on the tie, with an insulating pad laid between the rail base and the tie. Both edges of the rail base are held by plate springs that are fastened from above to the tie with bolts and nuts. Fastening devices of this type have presented problems, however, since the bolts and nuts can be easily excessively tightened, or alternately, the bolts and nuts can loosen as a result of the repeated passage of railroad cars or other wheeled vehicles over the rails. Consequently this conventional type fastening device has required substantial inspection and maintenance.
To overcome the above problems, other rail fastening devices have been devised which eliminate the use of bolts and nuts, and in place thereof position the spikes preset in the concrete tie so that the transverse or sideward forces imposed on the rail are imposed directly on the spikes. These fastening devices additionally employ a spring which coacts between the spike and the top surface of the rail flange for imposing a downwardly directed hold-down force on the rail. With fastening devices of this type, however, when the sideward or transverse pressure becomes excessive, it can cause breakage of the concrete tie due to the pressure being transmitted directly from the rail through the steel spikes onto the tie.
To eliminate the aforementioned problem in this latter type of fastening device, copending application Ser. No. 53 985, which is owned by the assignee of this application, discloses an improved elastic fastening device for a rail wherein the fastening device utilizes a pair of springs for securely positioning and holding the rail, one of the springs imposing a downwardly directed hold-down force on the top surface of the rail flange, and the other spring being positioned sidewardly between the side of the rail flange and a spring receiver for absorbing the transverse forces imposed on the rail. While the improved fastening device disclosed in this copending application has proven effective in absorbing the various forces imposed on the rail, nevertheless further developments have been made with respect to the fastening device so as to further improve upon said device.
Accordingly, the present invention relates to an improved elastic fastening device for a rail, which device permits elimination of bolts and nuts and at the same time permits utilization of a single spring which is capable of engaging both the upper and side surfaces of the rail flange, which spring thus imposes the desired hold-down force on the rail and at the same time absorbs the transverse or sidewardly directed load forces imposed on the rail. The improved fastening device of this invention thus provides for a secure fastening of the rail in a manner which can be carried out rapidly and efficiently so as to require minimal maintenance, and at the same time the improved fastening device accomplishes this objective with increased structural simplicity, including minimization of components. The fastening device of this invention is particularly desirable since it facilitates and speeds up the fastening of a rail onto its support.
An embodiment of the invention will be described by reference to the accompanying drawings, as explained below.